The present invention relates to a hook for single-cylinder circular knitting or stocking machines with cylinder and circular or semicircular plate.
Conventional single-cylinder circular knitting or stocking machines can close a longitudinal end of the tubular knitted item during its manufacture.
These machines are generally provided with a semicircular plate which is arranged above the needle cylinder of the machine and can be overturned, substantially through a 180.degree. angle, about a diametrical axis of the needle cylinder in order to face one half or the other of the needle cylinder.
Inside the semicircular plate there is a plurality of double radial grooves, and inside each double groove there are two or more hooks whose claw-shaped tips are mutually opposite. The hooks of each double groove can be actuated individually in order to engage the loops formed by the needles of one half of the needle cylinder and to retain them inside the claw-shaped tips during the overturning of the semicircular plate about the diametrical axis. After overturning, the hooks are actuated again so as to release the previously retained loops, which are engaged by the needles of the other half of the needle cylinder.
Through the transfer of the formed loops from one half of the needle cylinder to the needles of the other half of the needle cylinder, an axial end of the tubular item manufactured by the circular knitting or stocking machine is closed.
In order to engage and retain the loops of knitting during the overturning of the semicircular plate, it is necessary to use, for each one of the double grooves of the semicircular plate, at least one pair of hooks in which the tip directed towards the outside of the semicircular plate is claw-shaped and in which the claw-shaped tips of the two hooks are mutually opposite so that by means of the coordinated actuation of the two hooks along the corresponding double groove it is possible to open or close the claw-shaped tip of a hook by means of the claw-shaped tip of the other hook that is arranged adjacent thereto.
As a consequence of this fact, it is necessary to provide a plurality of double grooves inside the semicircular plate in order to accommodate and guide the two hooks.
Other machines use, in order to manufacture items with a closed axial end, a circular plate which is divided into two halves, a first one of which can be overturned below the other circular plate half in order to transfer the loops from the needles of one half of the needle cylinder to the needles of the other half of the cylinder.
In any case, the fact of having to provide two hooks for each loop of knitting to be transferred is a complication of the structure of the machine, also in view of the fact that the hooks of the various pairs must be actuated independently of each other in order to engage or release the knitting loops.